Following systemic delivery, an effective drug for a metastatic prostate cancer patient must selectively kill malignant cells without producing unacceptable off-target side effects (i.e., unacceptable levels of killing or injuring normal cells in host tissue). This is a daunting engineering challenge. Based upon the fact that cancer cells often acquire addiction to specific oncogenic signaling pathways, a new approach has emerged focused upon designing drugs to selectively inhibit only particular oncogenic signaling protein targets. In theory, such highly selective oncogene-based inhibitors target growth suppression and/or death of individual oncogene-addicted cancer cells sparing host normal cells. As a class, these new oncogene-targeted inhibitors are less toxic than chemotherapeutics, but they are not without side effects. More significantly, their therapeutic efficacy is limited by heterogeneity within the cancer cell population with regards to addiction to the specific oncogenic signaling resulting in drug resistance. Accordingly, new approaches are necessary to overcome tumor cell heterogeneity based therapeutic resistance.